The present invention relates to a memory device, and more particularly to a storage controlling and judging method of flash memory capable of reducing the erasing frequency of the flash memory to extend the service life thereof.
Presently, the flash memory has become popular because of its advantageous features, namely, nonvolatile, shock-proof, high storage capacity and others. Among many portable devices, the flash memory has taken the prominent place of EEPROM or the memory, which require battery. As the semiconductor technology has become mature nowadays, the storage capacity and transmission speed of the flash memory have been far upgraded then ever, and therefore the flash memory is applied in a broad field replacing the conventional storage media, such as the hard disk driver.
However, the flash memory has the hardware characteristics circumscription, the flash memory requires a new space management method and an efficient erasing strategy to evenly erase the storage block and reduce erase frequency to substantially upgrade the efficiency, extend the service life and reduce the power consumption of the system. Bad management method of the flash memory storage device could increase the cost and shorten the service life thereof.
Due to physical characteristics of the flash memory, after about a million times of erase operation, the flash memory gets damaged and should be replaced. Therefore, to reduce the erase frequency is a way for extending the service life of the flash memory. Referring to FIGS. 1, 2, 3, 4, 5 and 6, a conventional data writing method is shown, wherein when the manager prepares to write two pages from page 3 of block 0A into the flash memory, the flash memory finds a new block 1B and defines block 0A as an old block and moves the pages above page 3 of block 0A to block 1B; then the manager writes the page into page 3 and page 4 of block 1B and moves the pages below page 4 of block 0A to block 1B, finally, block 0A is erased and is replace by block 1B to complete writing.
A new block is required each data writing operation then the old block is erase, accordingly, the frequency of erase is higher and therefore the chances of damaging the flash memory is higher. Therefore, how to reduce the erase frequency for extending the life span of the flash memory, as well as increasing the storing speed thereof has become the important target for the manufacturers in the field.